This invention relates to the art of forming glass articles from molten glass, and more particularly to the forming of a plurality of virtually identical parisons or blanks by a single mold and plunger set, within a plurality of neck ring retainers continuously moving along a given linear path.
In the past, it has been known to form parisons for press and blow operations by conventional means such as the Hartford I.S. machine, the Miller press and blow machine and the Lynch MB machine. The Hartford I.S. machine utilizes a plurality of blank molds, each with its own plunger, blowhead and neck ring. With the mold, plunger and neck ring in position, a charge is received in the mold and blown down so that the plunger forms the finish in the neck ring. After a counter blow, the parison is completely formed and the blank mold opened with the glass parison held by the neck ring which is then rotated 180.degree. in a vertical plane to a position over a closing blow mold, wherein the neck ring is opened to release the parison into the blow mold and is then rotated back into position with the mold and plunger for a repeat cycle.
Both the Miller press and blow machine and the Lynch MB machine utilize rotating tables having a plurality of molds thereon for forming the parison, wherein the tables are rotated with an intermittent or cyclic movement such that molds stop at each station. Whereas the Miller press and blow machine uses one plunger for forming the blank and transfers the same by use of a neck ring, the Lynch MB machine utilizes individual plungers for each mold and transfers the parison from a blank mold table to a blow mold table by means of a swing transfer mechanism. A more complete explanation of the operation of the Hartford I.S. machine, the Miller press and blow machine and the Lynch MB machine is set forth on pages 326-339 of HANDBOOK OF GLASS MANUFACTURE VOL. I by Fay V. Tooley. However, from the foregoing it can be seen that the devices of the prior art not only functioned on an intermittent or cyclic basis in the production of parisons, but also required a plurality of mold and plunger sets so as to be available at each station and yet only productive at the pressing station.
U.S. Pat. No. 3,622,305 discloses a more recent concept in press and blow machines wherein a plurality of parisons are press formed by a plurality of mold and plunger sets as they rotate about a blank mold table. In U.S. Pat. Nos. 3,598,560 and 3,690,527, a plurality of continuously moving neck rings are mated with a plurality of continuously moving plunger type blowheads positioned thereabove and a plurality of continuously moving parison molds positioned therebelow. Although the parisons of the foregoing apparatus are formed in a continuously moving neck ring, such apparatus still requires the redundancy of multiple mold sets. U.S. Pat. Nos. 2,263,126 and 2,576,191, while utilizing only one mold set to consecutively form glass parisons, the parisons are not formed along a linear path or within the neck rings successively presented along such a path.
The present invention, however, discloses method and apparatus for successively forming parisons with a single mold and plunger set along a linear path and within successively presented neck rings continuously traveling along such path.
It thus has been an object of the present invention to improve upon the known technology of delivering and forming molten glass into parisons while minimizing the required number of mold sets and facilitating the handling of the newly formed parisons.